The present invention relates to power devices and related components thereof.
Electronic semiconductor device technology continues to rapidly advance, producing devices that achieve heretofore unattainable operating speeds, packing density, and high temperature compatibility. This last characteristic, high-temperature compatibility, is one of more important features. High-temperature environments as well as high-power and high frequency applications are becoming increasingly important. The ability of electronics to withstand high-temperature environments of gas-turbines, automotive engine compartments materials handling and fabrication equipment, aircraft subsystems and the like, makes possible many historically impractical electronic applications for these environments.
Many such high-power, high-temperature electronics applications inherently limit the ability to dissipate heat and power generated by the electronics. Thermal and power management as well as environmental protection of the electronics are therefore handled entirely by the electronics packaging. As a result, typical high-performance packaging criteria include mechanical strength, high thermal conductivity, close matching of device and package thermal expansion coefficients, low dielectric constant for accommodation of high frequency devices, and environmental protection (e.g., hermetic sealing).
In designing such packages, thermal management is important—especially at high power generation levels which increase the amount of heat created. Heat decreases the performance and operating life of the transistor. Moreover, heat generated at the collector base junction in bipolar devices can create a temperature buildup which may eventually cause the device to short-circuit. MOSFET switching losses and channel conduction losses cause the device to overheat and may result in failure.
Accordingly, the power device is generally mounted on a thermally conductive pad which acts as a heatsink and dissipates the heat generated by the power device. A copper plate is commonly used as a heatsink due to its good heat conductivity.